Receiver alignment measuring audio watts with what???

[Lkaskel]

Hey Gang,
I know that I have a few project questions posted on here but as I am working through some alignments I am curious what you use when aligning to a desired audio watts. As an example, when aligning a Uniden 858 board like in the President Washington and Robyn SB520 the requirement in the receiver alignment is to set your RF Gain and AM balance to .5 watts audio. What method and or piece of test equipment do you use to set to those parameters?

 

[Captain Kilowatt]

I have aligned a lot of receivers in my time but never heard of what you are talking about. Audio power from the AF section has nothing to do with aligning a receiver.

 

[Robb]

I have aligned a lot of receivers in my time but never heard of what you are talking about. Audio power from the AF section has nothing to do with aligning a receiver.

In this case CK, the service manual does call out the spec for audio level.

To answer the question, you use a volt meter set to AC with a dummy load or speaker, IIRC.

 

[Captain Kilowatt]

In this case CK, the service manual does call out the spec for audio level.

To answer the question, you use a volt meter set to AC with a dummy load or speaker, IIRC.

OK Never mind. Brain fart on this end. I misunderstood and thought he was talking about setting power out from the AF section. OK yes typical inject RF at a certain level and certain % modulation and align receiver for X power out from the speaker. Usually it states to align for a certain amount of voltage across the speaker leads which of course is a way of measuring power output. If the speaker impedance is 8 ohms you will achieve 0.5 watts output if there is 2 volts across the speaker terminals. The formula is voltage equals the square root of power times impedance. the procedure must indicate the position that the RF and AF gain control knobs must be preset too.

 

[Handy Andy]

May not be exact wording but found something similar...

You do have to take into consideration the quality of the speakers' volume...

 

[Tallman]

My B&K consoles has audio input with a resistive load and a watt meter for the audio. I don't use it for that purpose. I watch the scope for the highest peaks.

 

[unit_399]

Whenever I need to measure audio power, I use my old Heathkit audio vtvm.


-399

 

[unit_399]

My B&K consoles has audio input with a resistive load and a watt meter for the audio. I don't use it for that purpose. I watch the scope for the highest peaks.

Typically, if a receive tuneup requires setting an audio output level, a steady tone is inputted, so the average and peak audio output will be the same.

- 399

 

[kopcicle]

Same as the one on my bench

 

[Tallman]

Typically, if a receive tuneup requires setting an audio output level, a steady tone is inputted, so the average and peak audio output will be the same.

- 399

That's what the B&K consoles do. A modulated signal single tone for AM, Double for SSB alignments.

 

[unit_399]

That's what the B&K consoles do. A modulated signal single tone for AM, Double for SSB alignments.

Which B&K Console do you use?? I use a modified B&K E200D. Excellent features, Stable RF generator.

- 399

 

[Tallman]

Which B&K Console do you use?? I use a modified B&K E200D. Excellent features, Stable RF generator.

- 399

I have both the B&K1040 and the 2040. Once the oven for the crystal is warmed up it is rock steady. So are the audio tones.

 

[Low_Boy]

How about a synad meter

 

[unit_399]

How about a synad meter

I use a Helper Instruments SINADDER 3. Excellent piece of equipment.

- 399

 

[Low_Boy]

399....
Sometimes I do my alignment by ear then hook up the sinad and I seem to do just as good with out it lol.